Process for manufacturing nonwoven fabrics



Nov. 12, 1968 F., P. BARBONI PROCESS FOR MANUFACTURING NONWOVEN FABRICS Filed June 7. 1966 INVENTOR FRANCO PRPHLINI BHRBOM WM W0 W ATTORNEYS United States Patent 3,409,959 PROCESS FOR MANUFACTURING NONWOVEN FABRICS Franco Papalini Barboni, Barcelona, Spain, assignor to Resintex S.A., Barcelona, Spain Filed June 7, 1966, Ser. No. 555,817 Claims priority, application Spain, June 23, 1965,

314,818; Sept. 24, 1965, 317,787

2 Claims. (Cl. 28-72.2)

ABSTRACT OF THE DISCLOSURE An improvement in the manufacture of nonwoven fabrics is comprised of punching a needle having a hooked end in a down and up motion completely through a lap of loose fibers. As the needle emerges from the lap in its upward path it draws a beam of fibers from the lower face of the lap through its upper face. With the needle Withdrawn, the lap of fibers is displaced in the general direction of the fibers and as the movement of the lap is completed the needle again passes downwardly inserting the beam of fibers back into the lap at a different position. The cyclical down and up movement of the needle and the movement of the lap of fibers forms a continuous stitching of the fibers. A small portion of the fibers making up the lap have a welding rate different from the remaining fibers in the lap and the lap of fibers are consolidated by welding the fibers having a different welding rate from the other fibers in the lap.

This invention concerns improvements in the procedures for manufacturing nonwoven fabrics, and a method of intertwining their fibers.

The object of this invention is to produce a fabric or cloth from one or more layers of fiber laps, having a de gree of quality and a set of properties characteristically very similar to those of woven fabrics as produced through conventional weaving methods.

As is known, conventional woven fabrics, such as those made from warp and weft yarns, knitted fabrics, and others, exhibit specific properties, particularly those of shape retention, resiliency, stretchability, excellent foldability, transpirability, abrasion strength, and other desirable properties. All such characteristics are more or less marked, and they depend on the end-use intended for the fabric, on the type of fiber used in manufacturing the fabric, on its weave, on its finish, and on a number of other factors.

Several procedures have already been tried with a view to obtain products which can replace woven fabrics, particularly for interlinings, waddings and backings in (general, and others, but so far it has proved impossible to replace woven fabrics in making up garments or in producing similar textile goods.

An object of this invention is to effect improvements to obtain, from a mass of loose fibers forming one or more successixe layers, homogeneous or otherwise, through a combination of the methods described below, a cloth made of fibers, nonwoven, and provided with characteristics similar to those of woven fabrics, namely foldability into soft, nonrigid folds, a smooth feel and remarkable flexibility, while showing simultaneously a high level of tensile, rub, friction and similar strengths.

Essentially, the combination of the operations which characterize the improvements forming the object of this invention, is based on a special handling Off the loose fibers, to achieve their self-linkage within the lap, and on the welding of some such fibers, so that their self-linkage is thus consolidated. As a result of an efficient self-linkage of the fibers in the lap, it becomes possible to produce a strong cloth within low welding rates for the fibers, such welding rates having to be kept within very narrow limits in order that the finished prodnet is not deprived of its desirable properties, namely flexibility, a smooth feel, and other favourable conditions.

A further object of the invention is a method to achieve this particular intertwining of the fibers in the lap, through a suitable diaplacement of such fibers, thus causing their self-linkage.

For the purpose of better describing this method, the following isan outline of the various stages of its development, stressing particularly those operations having a greater significance.

To start with, in an early stage a loose fiber lap is obtained through any of the methods already known for the purpose.

The characteristics of this lap, both as regards quality and quantity of fibers, and the superimposition of layers or webs of either identical or dissimilar nature, will partially influence the properties of the finished product. As a necessary and sufficient condition for the success of this method, it will sufiice for a given proportion of the fibers forming the lap to exhibit welding rates differing from those of the remaining fibers in the mixture. Such proportion must be small, say from 1 to 10 percent, and may vary according to the characteristics of the fibers used for making such individual lap. Irrespective of this essential reqquirement, a lap may be formed of fibers of different qualities, enriching for instance one face with the best quality fibers, to obtain better results at a lower cost. Similar arrangements may be made in connection with all other characteristics, such as color, finish, and others.

Once the lap required has been formed, it is subject to a special punching operation, which is also an essential part of the method of the invention. By this punching, the natural structure of the lap, i.e., its particular fiber arrangement, goes through a substantial modification which will depend on the strength and such other features as are required in the end product.

As it is already known, the lap may be subject to the action of toothed steel needles, the teeth of which point towards the needle tip. Such toothed needles, by repeatedly piercing the mass of the lap, at right angles to its outer faces, modify the arrangement of some fibers, as these are drawn along by the needles in their movement, and are left laying across the general direction of all the remaining fibers in the lap.

In the improvements which are the object of this invention, the operation last described is replaced by a double-purpose punching, whereby some of the fibers are not only laid across the general fiber direction within the mass of the lap, but their self-linkage is achieved in the following manner. For this purpose the lap is pierced in a systematic way by needles having a hook fitted at the tip, so that, on the withdrawal of the needle, this hook draws along a beam of fibers making it travel upwards across the lap, until it reaches the upper face. On its travel, this beam loses a number of fibers and leaves them laying across the mass of fibers, until the hooked tip of the needle is no longer in touch with the lap. At this stage the lap is automatically moved aside so that the needle, on piercing its upper surface again, does so at a different place. This piercing takes place while its hook still holds some of the fibers drawn, and they are thus introduced again into the lap, to form, together with any other fibers freshly drawn, a downwards path in the opposite direction, until the lower face of the lap is reached by the needle tip. The insertion into the lap of fibers that were previously drawn from inside the same lap is helped by the toothed design of the needles, as their teeth serve to insert fibers into the lap as well as to draw along fresh ones to reinforce the former.

An endless, systematic punching operation as described results in a series of stitches made up from fibers of the lap itself, such stitches helping to bind the whole mass of fibers and to achieve full linkage between the two outer faces of the lap.

Through the method which is also an object of this invention, a perfect finish can be imparted to the lap, in such a manner that fibers are displaced without any stresses or breakages whatever, and a perfect intertwining of the fibers displaced is achieved, forming a sort of special stitching to make the lap into a fibrous body provided with excellent properties for a large number of end-uses.

The essential feature of this method is the lateral displacement of the lap as the needless start their downward travel from their raised position, carrying beams of fibers in their hooks. Such lateral displacement of the lap takes place over a distance not exceeding the length of the fibers drawn from the lap, that is, not exceeding the distance between the upper face of the lap and the lower tip of the needle, which starts coming down as the lap is drawn aside.

Thus the linkage of the fibers drawn upwards by the needle hooks is greatly improved, such fibers being laterally displaced together with the lap, since the punching operation causes no breaking stresses.

By using needles of a given diameter and of a given number of teeth, and by combining this with a lesser or greater raising of the said needles, which implies a specific rate of lateral displacement of the lap as well, it is possible to obtain different patterns of lap binding. As the case may be, fibers may be drawn from one single lap; from a composite lap made up of a number of webs; or from laps incorporating fibers of different types and colors. In this way it is possible to obtain a wide range of nonwoven fabrics provided with decorative patterns, suit able for a large number of end-uses.

By way of example, an embodiment of the present method of fiber intertwining will now be described with reference to the accompanying drawings, in which:

FIGURE 1 shows schematically an elevation of the device used for carrying out this method of fiber intertwining;

FIGURE 2 shows, also schematically and in successive stages, the punching process according to the method which is the object of the invention.

The method comprises the punching of a lap 1 by a set of needles 2 provided optionally with side teeth 3 pointing downwards, and ending necessarily in a hook 4 bent upwards. These needles are held by their upper ends in a support consisting of two plates 5 and 6, and are guided through a perforated plate 7 as the lap 1 as laterally drawn over a platform 8, also conveniently perforated. On top of the lap there is placed a further perforated plate 9.

All these plates and the platform mentioned are supported on struts 10, and the plates 5 and 6 carry the needles 2 which are vertically movable through the action of an adjustable cam 11, synchronized with the intermittent laternal displacement of the lap 1. The said plates 5 and 6 tend to attain their raised position through the action of a helical spring 12.

The lateral displacement of the lap 1 is effected through the action of two sets of rollers 13 and 14, one before and the other after the passage of the lap through the punching device, whereby a suitable layout of the lap under the action of the needles 2 is achieved, without any harmful stresses being developed in the lap.

According to this method, as the needles 2 come down (stage A in FIG. 2), and as the hook 4 pierces the full thickness of the lap while the latter remains still, the needles are arranged in such a manner that on their subsequent withdrawal upwards, they draw along fibers taken from the lower face of the lap, and these fibers come up together with the needles 2 and through the holes in plate 9 (stage B, FIG. 2), forming a beam of fibers drawn from the lap as the latter is held down by the said plate 9.

As the needles come down again, a gradual lateral displacement of the lap takes place in the direction of arrow X, over a distance similar to, but not exceeding, the length B of the beam of fibers F that was drawn up, or similar to, but not exceeding, the distance between the upper face of the lap and the lower tip of the needle.

By synchronizing the downwards motion of the needles and the lateral displacement of the lap, stresses are avoided in the beam. of fibers held by the needle hook. With a similar view, the distance over which the lap is laterally displaced is identical to the length of the beam of fibers, as described.

The lateral displacement of the lap stops shortly before the needless pierce again the lap as they come down, and subsequently the beam of fibers F that was previously drawn from the lap is introduced into it again, to be linked downwards (stage D, FIG. 2). The process is then repeated, the hook 4 taking fresh fibers F from the lap and drawing them upwards for their subsequent lateral displacement. In this way, a number of successive stitches are obtained in the lap, which stitches are made up of beams of lap fibers.

As mentioned above, by combining laps or webs of different colors, it becomes possible to produce fabrics with specific patterns or motifs, say stripes, checks or any other geometrical designs, their intensity depending on the proper combination of colors on both faces of the cloth, on the velocity of the lateral displacement of the lap, on the frequency of punching, and on the particular features of the needles used. To obtain a multicolored pattern on both faces of the cloth, laps may be used consisting of several webs of different colors, to be punched in sequential order, i.e., first two webs jointly, then the first two plus a third one, then the first three plus a fourth one, and so on, until a predetermined combination of colors has been obtained.

The device used for carrying out this method of intertwining fibers comprises means for adjusting the upwards or downwards displacement of the needles, and for synchronizing such displacement with the intermittent lateral displacement of the lap, for the adjustment of which there are also suitable means provided.

It will be understood from this description that the purpose of the perforated plate 9 is to prevent that, as the needles come up drawing beams of fibers F from the lower face of the lap, the lap is also raised, and the said plate holds the lap down while the holes in it allow the passage only of the said beams of fibers and, of course, of the needles carrying them. This perforated plate may, however, be replaced by any other means fulfilling the same purpose of lap retention.

Once the self-linkage of the fibers has been achieved through the application of the method described, consolidation of such linkage is sought through the welding of part of the fibers in the lap. As is mentioned at the beginning, the tap should contain a proportion of fibers exhibiting welding rates different from those of the other fibers remaining in the lap (for instance, a given proportion of fibers liable to heat welding at a lower temperature than the rest, or of fibers liable to chemical welding only, such as by solvents). According to the nature of these specific properties, heat or chemical welding, as the case may be, is performed, so that these fibers are Welded to one another on establishing contact, irrespective of their particular welding rates. The success of this method depends on the difference in properties between those fibers that weld and those that do not weld. Results depend also on the distribution within the lap of the fibers that weld. Such distribution may be regular throughout the lap, or else be concentrated on both faces of the lap, according to the characteristics required for the end product. It will be realized that, according to the type of welding chosen, the lap may be submitted, prior to this operation or simultaneously with it, to all such auxiliary treatments as may warrant optimal results.

The method described may be supplemented by dyeing or finishing operations, which may be similar to those already applied in the textile trade to woven fabrics, always according, of course, to the nature of the fibers in each case.

As a result of the method described, a fabric is obtained, nonwoven and of fibrous composition, but with characteristics similar to those of woven fabrics, which fabric is much easier to manufacture and at a much lower cost. Such fabric or cloth may be used by the textile trade, or for decoration, furnishing and similar purposes.

The need for the lap to contain a given proportion of fibers able to consolidate their self-linkage through welding, requires that such fibers exhibit a specific property, namely their ability to weld. The remaining fibers in the lap may be of any nature whatever, even including fibers of different origins, either natural or synthetic. Such freedom in the choice of the fiber source influences costs most favourably, particularly as the nobler fibers may be concentrated on one face only of the lap, the rest being made up or poorer quality fibers. A large number of other combinations are likewise possible.

Although the invention has been specifically shown and described, it will be obvious to those skilled in the art that it is not so limited, but that it is susceptible of various changes and modifications without departing from the spirit thereof, as covered by the claims which follow.

What is claimed is:

1. Improvements in the manufacture of nonwoven fabrics, whereby a lap made up of loose fibers, a small proportion of which exhibit Welding rates different from those of the remaining fibers in the lap, is subject to systematic punching, whereby beams of fibers are drawn into the lap from one of its faces towards the opposite face, such fibers forming, as they are laid along their path across the general direction of the fibers in the lap, a sort of stitch reaching from one such face of the lap to the opposite one; are subsequently laid over the latter face, and enter the lap again at another point slightly displaced laterally, to reach down to their original level inside the lap, thus binding fully the mass of the lap, and consolidating this binding through welding those fibers which exhibit welding rates different from those of the remaining fibers in the lap.

2. Improvements in the manufacture of nonwoven fabrics, whereby the systematic punching according to claim 1 may be performed through a device provided with needles terminating in a hook, the said needles piercing the lap at right angles to one of its faces, traversing the lap until the said hook comes out at the opposite face, and drawing along a beam of fibers across the lap, until it also comes out at the said opposite face, at which stage the lap is laterally displaced with respect to the needles, which, on coming down again into the lap, pierce it at a different point of its surface, where they introduce those beams of fibers still retained by their hooks, thus forming a sort of continuous stitch, the said needles remaining, after they have gone across all the lap, in a raised position suitable to start a fresh stitch.

References Cited UNITED STATES PATENTS 1,314,565 9/1919 Billington 2872.2 2,297,440 9/ 1942 Szues 66-84 2,978,786 4/1961 Turner 28-72.2

FOREIGN PATENTS 900,056 12/ 1953 Germany. 801,440 9/ 1958 Great Britain. 826,163 12/ 1959 Great Britain.

LOUIS K. RIMRODT, Primary Examiner. 

